280vs electrical problem; won't start.

[kieranto]

hello to all,
assistance required if possible; my 280vs won't start from the button, in fact nothing on the front panel works apart from the indicator and tacho lights. however, the machine runs in forward and reverse when the relative contactor is held in.
I'm an engineer with just a bit more than basic electrical knowledge. can anyone help with information or a wiring diagram.
brian.

[LesT]

I can't help with a wiring diagram for the Lathe Power controls.
But, in general terms, there must be an auxilliary circuit which operates the contactors when you push the forward or reverse button in. This might be a low voltage circuit fed from a transformer or it might be a single phase supply. (As you mentioned a Forward and Reverse drive I assumed you have three phase supply, but I might be wrong).
Anyway:
Using a voltmeter (usual safety warnings for live work apply here).....
Is there any voltage on the auxilliary circuit ?
Is there an auxilliary fuse, which is blown ?
Is there an interlock circuit ?, are doors open switches made etc ?
Are the contactor close coils open circuit ?
Are there any overload units which are tripped ?, are all the fuses OK ?
Thats all I can suggest I'm afraid.
Perhaps if you took some pictures and posted them someone might spot something.

[kieranto]

hello and thanks very much for your help.
I have a meter and will attempt to check it out tomorrow.
I don't think photos would help as all wiring seems to be original and tight but will post tomorrow.
thanks again, brian.

[Andy B]

Does your lathe have the control panel above the headstock, or on the front of the cabinet stand?
If the former, then it is like mine - and I know the electronics well as I had to completely rebuild mine - see here: viewtopic.php?f=14&t=2268&p=8001&hilit=+circuit#p8001.
I have a wiring diagram somewhere.

I assume you've you've opened the control panel and checked for any obviously loose wires?
Defintely worth checking the interlock switches - mine has a kick-switch and one on the gear-guard door.
I kept having problems with the lathe suddenly stopping (always started fine). I initially thought it was a thermal cut0out problem, but eventually tracked it down to a dry joint on the door microswitch (and kicked myself for not checking it sooner!).

From Les's suggestions:
Is there any voltage on the auxilliary circuit ? - yes there must be (lights are on). Mine has a 24V transformer for this supply.
Is there an auxilliary fuse, which is blown ? - Lights would be out if this was the case
Is there an interlock circuit ?, are doors open switches made etc ? See above
Are the contactor close coils open circuit ? - Possible - OP did not say if the contactors are latching on when manually operated

Are there any overload units which are tripped ?, are all the fuses OK ? - If like mine, there are thermal cutouts but these would not enable operation when the contactors are manually activated as they are in the motor line voltage cables

Andy

[kieranto]

hello andy and thanks,
my lathe is same as yours.
no loose wires, 1 interlock on door, all fuses ok, the contactors don't latch when manually operated and overloads ok.
I think that the door switch may be at fault as, when the start button is held in and the switch plunger moved in various directions, the machine starts and runs until the switch is let out to the door open position.
wiring diagram would be a boon as two of the contactors are upside down making the wiring very difficult to follow.
there may have been a link between two of the contactors as, when I removed the guard there was a short wire lying on the bottom and a loose contactor wire.
followed your link; what a disaster. you must have been very disappointed ( for want of a stronger phrase) when you saw that. all's well that ends well, you've made a great job of the repair.
brian.

[Andy B]

Hi Brian,

Sounds like a dodgy switch, doesn't it. Hopefully easy to sort, then.

I've found a pile of wiring diagrams including the 280VS (original and later versions) - but they'll need repair over the weekend before I can run them through a large format scanner next week.

Andy

[kieranto]

thanks andy,
is there anything I can do with the switch?
brian.

[Andy B]

Can you post a picture so we can see what sort of switch it is?
I think a variety may have been used over the years, and of course they may also have been replaced in service.

Andy

[Pete.]

Seems pretty clear to me that the door switch is faulty. Join the wires to test it.

If it does happen to be something else I have here the wiring mapped out for the gang of three contactors (fwd, rev and pump) on my synchro.

[rpwilson]

The door switch on mine has been disconnected, I imagine when it had the inverter installed. Its still on the machine, so if yours is faulty, you can have mine if you want it. Its a 280 Synchro with the manual speed change, not the 280 VS, but I imagine the door switches were the same.

Richard

[kieranto]

hello andy, pete and Richard,
thanks once again for your help.
I got a new telemechanique switch last night from a friend so that possible problem has been fixed but it still won't start without holding the contactor in.
I have an electrician coming later in the week so hopefully he'll be able to work it out.
brian.

[Andy B]

Wiring Diagrams for 280VS (Pendant control) & Synchro lathes here

I'll see if I can get the mods to chnage the title of that section, then put some more 280 lathe drawings in there as I scan them.
....Edit - now done, and I've amended a few other titles to hopefully make the content clearer....

Andy

[kieranto]

hello andy,
I've printed the wiring diagrams and awaiting the electrician. hopefully all the info he requires will be at his fingertips.
thanks again and to all who helped or were willing to help in this matter.
brian.